RESULTS OF EXAMINATIONS. 



23 



olooresins it has been found that those of a stringy, viscous, and 

 homogeneous character foam badly on distillation, give up their vol- 

 atile oil with difficulty, and yield a much darker rosin than is to be 

 expected from " virgin gum." On the other hand, oleoresins, from 

 which the resin acids crystallize and settle out on standing, distill 

 quietly and yield light rosins. The foaming and darkening of the 

 rosin is due partly to the presence of trash, such as needles and chips, 

 and partly to the absorption of oxygen previous to distillation. 



EXAMINATION OF THE VOLATILE OIL. 



PHYSICAL PROPERTIES. 



An oil obtained from oleoresin collected during 1911 had the fol- 

 lowing properties: Specific gravity, 0.8663 ; index of refraction, 1.4728; 

 specific rotation, [a] D = + 10.42. Another sample of the oil, amount- 

 ing approximately to 375 grams, the analysis of which is given in 

 Table 4, had a specific gravity of 0.8658 and an index of refraction 

 of 1.4727. 



TABLE 4. Fractional distillation of the volatile oil of Pinus lambertiana. 



IDENTIFICATION OP THE CONSTITUENTS. 



a-pinene. The physical properties of the fractions show that 

 the oil consists largely of a-pinene. For further proof a d-rotatory 

 fraction (00200= +13.08) boiling between 156 and 157 was treated 

 with nitrosyl chloride. The pinene nitrosochloride obtained from this 

 treatment melted at 103 after several precipitations from chloroform 

 with methyl alcohol. 



fi-pinene. That portion of the oil boiling between 160 and 168 

 was oxidized with potassium permanganate to determine the presence 

 of /?-pinene. A small amount of nopinic acid, the characteristic 

 oxidation product of /?-pinene, was obtained. The acid melted at 

 125. 



